Single Channel 31-band Graphic Equalizer
with FDC - Feedback Detection Circuit


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The HQ-31 features ART’s trademark FDC [Feedback Detection Circuitry]. The ART proprietary FDC differs from similar systems in that it is extremely fast. Although it illuminates the band with the greatest energy with the brightest LED, it doesn't fully discriminate between bands and will not get "stuck" on one band when there is no signal.

The HQ-31 utilizes a set of indicators that show which of the many EQ bands has the greatest energy. The LED indicators can immediately show which band corresponds to the feedback frequency, allowing the sound engineer to reduce gain in that band to quickly kill the feedback while having minimal impact on the sound of the live programme material.

The FDC also acts as a simple spectrum viewer while the concert proceeds showing where the “hot” areas are. During system setup and sound check, the FDC may be used to help identify room and sound system resonances. By increasing the gain until feedback occurs, it is easy to identify those frequencies that are likely to be problems. Reducing the gain in these bands helps tune the sound system and remove problem areas before the show begins. It also helps increase the gain margin before feedback, otherwise known as the gain-before-feedback ratio.

The unit also features constant Q circuitry, 45mm centre detente sliders with selectable boost or cut within a range of 6 or 12 dB, electronically balanced XLR, ¼” TRS and unbalanced RCA input and output connections, high and low pass filters, LED level metering, variable input controls, signal clip level indicators, ground-lift switch, internal power supply and selectable line voltage. The rugged, all-steel chassis occupies a 2U-rack space and is intended for installation into standard 19” equipment racks.

Applications for the HQ-31 include Live Sound Reinforcement Systems / PA, Permanent or Fixed Installations, Church, Club, Practice Studios, Disco Systems, Broadcast / Recording and Studio / Field Monitoring Systems.


Variable Input Gain Control

Signal Clip Level Indicator

Ground-lift Switch

Internal Power Supply

Selectable Line Voltage

Single Channel 31-band Graphic Equalizer

FDC - Applied Research & Technology's proptietary Feedback Detection Circuit (TM).

Ultra-fast Input Level LED Bargraph Metering on Each Channel

Accurate Constant-Q Filtering

Full Long-throw 45mm Center-Detented Frequency Band Sliders

Independent Level and Bypass Controls

Relay True-bypass - If Power is Lost, Signal Will Still Pass / Throughput

Occupies 2 Rack Spaces


Live Sound and Public Address Systems

Permanent and Fixed Installations

Church Sound Systems

Nightclub Sound Systems

DJ and Karaoke Sound Systems

Broadcast and Professional Recording Studio Systems

Stage / Foldback Monitoring Systems

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